Flowchart symbols and what they mean

Flowchart symbols are a shared vocabulary. A diamond means a decision; a rectangle means a step. When everyone reads the shapes the same way, a chart can be understood without a key.

That shared understanding is strongest for a handful of shapes and fades quickly after that. This reference starts with the core symbols almost everyone recognises, then covers the specialised ones and when they are worth using.

The four core symbols

These four are enough for most business processes. If your audience is mixed (managers, new hires, clients), stay within them.

Symbol	Shape	Meaning	Label style
Terminator	Rounded rectangle or oval	Where the process starts or ends	“Order received”, “Order closed”
Process	Rectangle	A step someone or something performs	Verb first: “Check stock”
Decision	Diamond	A question with two or more outcomes	A question: “In stock?”
Flow line	Arrow	The direction from one symbol to the next	Labels only on decision exits

Terminator

Every flowchart should have exactly one start. It may have more than one end, for example “Order shipped” and “Order cancelled”. Keep terminator labels short and describe a state or event, not an action.

Process

The workhorse. Each rectangle should describe one action at a consistent level of detail. “Prepare invoice” and “Type customer GST number” don’t belong side by side; one is far more detailed than the other.

Decision

A diamond asks a question, and each arrow leaving it carries an answer. Yes/no questions are clearest. If a decision has three outcomes, such as “Priority?” with high, medium and low, label every exit and keep the arrows well separated.

Flow line

Arrows should point in a consistent overall direction, top to bottom or left to right. Avoid lines that cross. Where crossing is unavoidable, a small bridge or hop at the crossing point makes it clear the lines aren’t connected.

Common supporting symbols

These appear regularly and are reasonably well understood, though not universally. Use them when they add information the reader needs.

Symbol	Shape	Meaning
Input/output	Parallelogram	Data entering or leaving the process, such as “Receive form” or “Send report”
Document	Rectangle with a wavy bottom edge	A document produced or used, such as an invoice or contract
Multiple documents	Stacked wavy rectangles	Several documents of the same kind
Predefined process	Rectangle with double vertical sides	A sub-process documented in another chart
Database	Cylinder	Stored data, such as a customer database
Manual input	Rectangle with a sloped top	Data typed in by a person

The predefined process symbol is the most useful of these. It lets you keep a chart short by collapsing a detailed sequence into one box, with a note saying where the detail lives. For example, “Run credit check (see Credit process)” replaces ten boxes with one.

Connector symbols

Large charts sometimes need to jump from one place to another without a long line.

• On-page connector: a small circle containing a letter or number. Place matching circles where the line leaves and where it resumes.
• Off-page connector: a pentagon shaped like a home plate, used when the flow continues on another page.

Connectors make readers hunt. If you need more than two or three, split the chart into an overview and sub-processes.

Less common symbols

Formal standards include further shapes, such as delay (a D-shape), preparation (a hexagon) and manual operation (a trapezoid), with precise meanings in engineering documentation.

For a general business audience, these shapes tend to be read as decoration rather than meaning. If you use them, add a legend. If you’re unsure whether readers will recognise a shape, use a plain rectangle and say what’s happening in the label instead: “Wait 48 hours for supplier reply” is clearer to most people than a delay symbol.

Choosing symbols for your audience

A practical way to decide how many symbols to use:

1. General audience (leadership, clients, new hires): the four core symbols only.
2. Operational teams who use the process daily: core symbols plus document, input/output and predefined process.
3. Technical or systems teams: the full set, with a legend if the chart will travel beyond the team.

The aim is that nobody has to stop and work out what a shape means. Procedure charts for new starters are a good example of the second group; SOP flowcharts shows how to build one from a written procedure.

Conventions that make symbols readable

Shapes only work if they’re used consistently. A few habits help:

• One meaning per shape. Don’t use a rectangle for steps and also for notes. Put notes outside the flow, as plain text or a comment.
• Same size for the same shape. Varying box sizes suggest a hierarchy that isn’t there.
• Colour supports, it doesn’t define. You can colour decisions differently, but the diamond shape should carry the meaning on its own, so the chart still works in black and white.
• Labels inside, not beside. Each symbol should carry its own short label.

For a full method of putting these shapes together, from scoping the process to checking it with real cases, see how to make a flowchart.

Quick reference

• Oval: start or end
• Rectangle: do something
• Diamond: decide something
• Arrow: go next
• Parallelogram: data in or out
• Wavy rectangle: a document
• Double-sided rectangle: see another chart
• Cylinder: stored data
• Circle: jump to a matching point

When you describe a process to DiagramsPro in plain words, it chooses these standard shapes for each step and decision.